Method for treating a running fabric web

ABSTRACT

A method and associated apparatus of modular construction is provided for treating a running fabric web with various chemicals, such as scouring solvents, and then drying the web by the use of super-heated solvent vapor and air as the drying agent in a closed system. A multi-stage solvent treatment station is provided wherein each stage continuously re-cycles a portion of the solvent to provide maximum solvent flow and cleaning action with a minimum amount of solvent. Additional chemical application stations are provided for applying selected chemicals to the fabric at different stages in the treatment process.

United States Patent Holm Dec. 2, 1975 [5 METHOD FOR TREATING A RUNNING 2.817.227 12/1957 Eriksson (58/205 R x FABRIC WEB 3,365.752 1/1968 Farel1..... 68/205 R X 3,643,475 2/1972 Stevens 68/18 C Inventor: Wllllam J- Holm, p ingfield, Vt. 3.750.428 8/1973 Bruckner (18/3 ss [73] Assignee: Riggs & Lombard, Inc., Lowell,

Mass Primary Exammer-Harvey C. Hornsby Assistant ExaminerPhilip R. Coe 1221 Flled? 1974 Attorney, Agent, or Firm-Morse, Altman, Oates & 211 App]. No.: 460,926 B8110 Related US. Application Data [57] ABSTRACT [62] g g g gg A method and associated apparatus of modular construction is provided for treating a running fabric web with various chemicals, such as scouring solvents, and [52] us then drying the web by the use of super-heated solvent [51] Int CHWDMB U02; D0613 15/04; DO6B 21/00 vapor and air as the drying agent in a closed system. A

[58] Field of Search 8/151, 151.2, 158;

68/3 SS, 19.1, 18 C, 20, 205 R References Cited UNITED STATES PATENTS 1,387,072 8/1921 Putnam 68/20 X 1,527,369 2/1925 Meyer 8/158 X 2,176,705 10/1939 Derby 68/18 C X STORAGE STILL multi-stage solvent treatment station is provided wherein each stage continuously re-cycles a portion of the solvent to provide maximum solvent flow and cleaning action with a minimum amount of solvent. Additional chemical application stations are provided for applying selected chemicals to the fabric at different stages in the treatment process.

1 Claim, 1 Drawing Figure //0' 32 /30, l @y Q E //0 l 5 I06 [22 m 426 rl irl;

U.S. Patent Dec. 2, 1975 Lj v mQqmOPm NOZ JduzzwIo METHOD FOR TREATING A RUNNING FABRIC WEB This is a division of application Ser. No. 207,430, filed Dec. 13, 1971, and now US. Pat. No, 3,803,879.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the treatment of textiles and more particularly is directed towards a new and improved method for solvent scouring a running fabric web.

2. Description of the Prior Art During the production of many types of textile fabrics, it usually is necessary to clean or scour the fabric in order to remove a variety of impurities natural to or collected by the fabric. The scouring process and subsequent drying preferably should be carried out with the fabric in a fully relaxed condition to avoid stretching or otherwise distorting the material. This is particularly true with respect to knit goods which are fragile and easily stretchable. While it is desirable to have a large volume of scouring solvent washing through the fabric in order to provide a thorough cleansing action,

' it becomes quite expensive to achieve this in view not only of the high cost of the solvent itself, but also the storage requirements which must be provided where a large quantity of solvent is used. Heretofore, scouring equipment together with associated solvent storage tanks have occupied a large amount of floor space. Further, equipment'of this type has been relatively fixed in design and lacking in flexibility for performing other textile processing operations.

Accordingly, it is an object of the present invention to provide a new and improved method and associated apparatus for treating a running fabric web. A more particular object of this invention is to provide a new and improved method and apparatus for solvent scouring a running web on a continuous basis providing a high washing action with a minimum volume of solvent. A further object of this invention is to provide a novel method and apparatus for drying the fabric without distortion thereof.

SUMMARY OF THE INVENTION This invention features the method and for treating a running fabric web, comprising delivering the web in a tensionless flat condition onto a conveyor and carrying the web past a plurality of scouring stations with each station re-cycling a portion of solvent drains as well as a portion of the adjacent station drains, then past a final station wherein clean, fresh solvent is applied. The web is then carried through a suction station where a portion of the solvent is removed and then past an optional application station where a chemical may be applied to the web. The web is then carried into a drying chamber where it is transported in a flat, tensionless condition over a plurality of vibratory conveyors providing bulking action to the material while it is subjected to a combination of air and super-heated vapor used to flash off solvent entrained within the material. A second optional application station is provided in the drying section to apply additional chemicals to the web prior to leaving the drying chamber. The apparatus is in a modular configuration to permit extension of the unit or the insertion of additional stages to the same basic unit.

BRIEF DESCRIPTION OF THE DRAWINGS The FIGURE is a sectional view in side elevation, somewhat schematic, of a fabric treating apparatus made according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, the reference character 10 generally indicates a fabric treating apparatus comprised of modular housing sections 12 and 14 detachably connected to one another along a vertical joint 16. In general, the forward section 12 serves as a solvent scouring chamber while the after section 14 serves as a drying chamber. The apparatus 10 is mostly enclosed within a housing formed by side walls 18 and 20, end walls 20 and 22, bottom walls 24 and 26 and top walls 28 and 30.

A running web 32, which may be in flat open width form as for woven fabrics or in flat tubular form as for knit fabrics, is carried up in an inclined conveyor 34 and dropped down onto an inclined chute 36 extending into the first stage 12 and terminating slightly above the upper reach of a horizontally extending conveyor 38. A feeler 40 is located between the discharge end of the chute 36 and the start of the conveyor 38 to sense the tension on the web 32 as it is delivered onto the conveyor. The feeler is operatively connected to one of the drying rolls for the feed conveyor 34 and serves to control the rate of delivery of the web into the scouring chamber. If the feed is too fast, the web will drape loosely as it comes off the chute whereas if the feed is too slow, the web will become tensioned. In any event, the feeler will sense the condition and, through the control unit, take corrective action.

Mounted above the upper reach of the conveyor 38 are banks of spray heads or nozzles 42, 44 and 46 arranged in spaced parallel relation transversely across the conveyor and positioned to spray the web 32 with solvent as it is carried underneath. Typically, each group of spray nozzles may be three in number and typically may be in the form of tubes or pipes formed with longitudinal slits or longitudinally aligned perforations adapted to dispense the solvent in the form of a spray against the web. Each set of nozzles is connected by its own conduit 48, 50 and 52, respectively, to its own pump 54, 56 and 58, respectively. Each of the pumps is connected by a conduit 60, 62 and 64, respectively, to a drain tank or a trough 66, 68 and 70.

The drain troughs 66, 68 and 70 are mounted adjacent to one another in a vertically staggered relation with the tank 66 below the level of the tank 68 which, in turn, is below the level of the tank 70. The drains from the nozzles above the conveyor collect in the troughs with most of the drains running down an inclined wall 72 into the first trough 70. The wall 72 is located directly below a nozzle or spray bar 74 positioned at the end of the nozzle sets 42, 44 and 46 and connected by a conduit 76 to a still 78 whereby clean, fresh solvent only will be sprayed onto the web prior to leaving the scouring chamber. Thus, the trough 70 in conjunction with the pump 58, conduits 62 and 64 and sprayheads 46 re-circulate relatively clean solvent at this stage since it is closest to the fresh solvent coming from the nozzle 74. The overflow from the trough 70 goes into the middle trough 68 which also receives some drain from its associated nozzles directly over it and which drains include those impurities washed down by the set of nozzles 42. Thus, the second set of sprayheads 44 wash the fabric with solvent that is less clean than the solvent going through the sprayheads 46, yet cleaner than those at the first set of heads 42. The overflow from the trough 68 is to the trough 66 which is recycled to the first set of nozzles 42 by means of a pump 54. Since the fabric entering the first part of the scouring station receives its first cleaning at the first station the solvent being circulated will be relatively dirty in comparison with the other stages wherein the solvent becomes successively cleaner until it passes the nozzles 74 where completely clean, fresh solvent is applied and at which point the fabric is fully scoured. The recycling of the solvent in this fashion provides a very high capacity of washing action which is extremely effective and keeps to a minimum the total quantity of solvent required, despite the high pumping volume. The overflow from the trough 66 is to a collection drain 80 which feeds through a line 82 and is pumped back to the still 78 where the solvent is purified and returned to the scouring station through the line 76. A storage tank 84 is provided and connected to the still to compensate for losses due to evaporation leakage and the like.

The scouring action is further enhanced by vibrating the web as it passes through the scouring station. This may be done by means of an eccentrically rotated roller 85 mounted below the upper reach of the conveyor 38.

As the fabric is carried by the conveyor 38 out of the scouring chamber, it is carried over a slit suction pipe 86 mounted below the upper reach of the conveyor belt and connected by a line 88 to a vacuum pump 90 which discharges the recovered solvent back into the still. In practice, the conveyor belt 38 is in a form of a foraminous screen or mesh material which permits the solvent to pass freely therethrough. By re-cycling the solvent in this fashion, the cleansing action is multiplied. For example, assuming the pumping capacity from the still is 600 gallons a minute, this washing volume would be multiplied approximately four times by the re-cycling stages, the multiplication factor depending upon the number of re-cycling stages.

From the suction box 86, the conveyor 38 carries the web under a spraybar 92 adapted to deliver a liquid chemical over the width of the fabric. The spraybar is connected by a line 94 and pump 96 to a storage tank 98. A drain board 100 is located below the upper reach of the conveyor and under the spraybar 92 to collect the runoff from this station. A drain return line may be provided to recover excess chemical and return it to the storage tank 98. Various types of chemicals may be applied at this station such, for example, a finishing chemical sold under the trademark Scotchguard by the 3M Company.

From this finishing station, the web is transported into the drying section 14 and is discharged from the conveyor 38 onto the upper reach of a conveyor 102, preferably of an openwork material to permit vapors to pass therethrough. The conveyor 102 is disposed slightly below the level of the conveyor 38 and a feeler 104, similar to the feeler 40, is provided to sense the tension of the web as it moves from one conveyor to the other. As before, the feeler 104 is operatively connected to the conveyor 102 to control the speed thereof to prevent tensioning of the web and also to prevent the web from bunching up. Insofar as the web will be drying while it is on the conveyor 102, it will undergo dimensional changes to some extent depending upon the material. Thus, unless compensation is provided in the speed of the conveyor 192, the web would tend to tension longitudinally with respect to the section of the web passing through the scouring station.

In order to aid in removal of the solvent from the web and also to provide bulking action, a vibratory motion is introduced to the web. In the illustrated embodiment, the vibratory action is provided by means of an eccentric roll 106 below the upper reach of the conveyor belt 102 and rotated by any suitable means such as a motor and the like. Rotation of the eccentric roll 106 will agitate and vibrate the conveyor belt together with the web, tending to shake out droplets of solvent within the web fibers and also fluffing up the web material in the process.

The main drying action in the drying chamber is provided by means of a combination of super-heated solvent vapor and air which is delivered through ducts 108 and 110 disposed above the upper reach of the conveyor 102 and provided with openings along their bottom walls to direct heated gas down against the web. Air and solvent vapors are continuously re-circulated within the drying chamber and provide a highly effective medium for drying the fabric. The mixture of air and solvent along with any solvent flashed off from the web by the drying action, is drawn down towards the bottom of the drying chamber through condensers 112 mounted across an opening formed in a horizontal supporting wall 114. A portion of the vapors passing through the condensers will condense and collect in one of the troughs formed in a drainboard 116 and these drains are then returned to the still for re-use. The remaining gaseous mixture of air and vapor is drawn into a centrifugal blower 118 and forced into a manifold 120 across which is mounted a heater 122. The heater superheats the vapor for optimum drying action prior to distribution through the transversely extending ducts 108 and 110 disposed across the conveyor 102 and communicating with the heater manifold.

From the conveyor 102 the web is transported upwardly to another horizontal conveyor 124, the speed of which is controlled by means of a feeler 126 and which also is provided with a vibrator 128. Ducts 108 and 110 are located above the conveyor as in the first instance. Disposed above the upper reach of the conveyor 124 is another discharge head 130 providing a second fabric finishing station wherein a chemical, which may be the same as or different from the chemical at the first finishing station, is applied to the web. The head 130 is connected by a conduit 132 and a pump 134 to a chemical storage tank 136.

The web is then carried along a reversely extending path and is fed up onto the uppermost conveyor 138, the speed of which is controlled by a feeler 146 where it is carried upwardly and outwardly through the end of the drying chamber to be delivered to a take-up roll or transferred to other processing equipment.

By virtue of the modular construction, the scouring and drying sections may be separated to permit the addition of other fabric processing equipment, to extend the length of the conveyors, to add heating sections, provide more finishing stations,- provide additional washing action, or the like. This provides a high level of flexibility since the units may be used together, in

6 conjunction with other equipment or by themselves, as c. collecting the drains from one flow and recycling desired. at least a portion of the drains in another flow,

Having thus described the invention what I claim and d. directing a flow of fresh liquid onto said web after desire to obtain by Letters Patent of the United States said separate flows and collecting the drains is: 5 thereof for recycling in said separate flows,

1. The method of treating a running fabric web, come. applying a vacuum to a portion of said web to reprising the steps of, move at least some of said liquid therefrom after a. transporting said web in a flat relaxed condition said web has received a flow of fresh liquid, and,

longitudinally along a horizontal path, f. transporting said web in a flat relaxed condition b. directing separate flows ofa treatment liquid trans- 10 along a second predetermined path and directing a versely across the upper surface of said web at difflow of a heated gas including vaporized treatment ferent longitudinally spaced positions along said liquid over said web while agitating said web. path while agitating said web, 

1. THE METHOD OF TREATING A RUNNING FABRIC WEB, COMPRISING THE STEPS OF, A. TRANSPORTING SAID WEB IN A FLAT RELAXED CONDITION LONGITUDINALLY ALONG A HORIZONTAL PATH, B. DIRECTING SEPARATE FLOWS OF A TREATMENT LIQUID TRANSVERSELY ACROSS THE UPPER SURFACE OF SAID WEB AT DIFFERENT LONGITUDINALLY SPACED POSITIONS ALONG SAID PATH WHILE AGITATING SAID WEB, C. COLLECTING THE DRAINS FROM ONE FLOW AND RECYCLING AT LEAST A PORTION OF THE DRAINS IN ANOTHER FLOW, D. DIRECTING A FLOW OF FRESH LIQUID ONTO SAID WEB AFTER SAID SEPARATE FLOWS AND COLLECTING THE DRAINS THEREOF FOR RECYCLING IN SAID SEPRATE FLOWS, E. APPLYING A VACUUM TO A PORTION OF SAID WEB TO REMOVE AT LEAST SOME OF SAID LIQUID THEREFROM AFTER SAID WEB HAS RECEIVED A FLOW OF RESH LIQUID, AND, F. TRANSPORTING SAID WEB IN A FLAT RELAXED CONDITION ALONG A SECOND PREDETERMINED PATH AND DIRECTING A FLOW OF A HEATED GAS INCLUDING VAPORIZED TREATMENT LIQUID OVER SAID WEB WHILE AGITATING SAID WEB. 